1. Field of the Invention
The present invention relates to a valve apparatus, an more particularly, to a valve apparatus which is installed in a movable oxygen cylinder so as to be used as a post valve for an oxygen generation system for household use or a post valve for general medical care.
2. Description of the Related Art
According to a lot of standards established by the Compressed Gas Association (CGA), a post valve for medical care which is combined with an ambulatory oxygen cylinder adopts a particularly different valve, gas line, connector considering the kind of gas which is used therein. For example, outlet connect fittings for a gas cylinder are designated according to CGA-870 regarding the gas cylinder in which 93% oxygen has been charged and CGA-950 regarding the gas cylinder in which the gas for medical care has been charged, respectively. As these standards are designated as size of fittings that are incompatible with one another, the fittings are prevented from improperly crossing and being connected with each other.
In this case, a CGA-870 post valve includes a CGA-870 port in order to supply oxygen discharged from an oxygen cylinder to a patient. According to regulation of the American Food and Drug Administration (FDA), an oxygen generation apparatus for household use is made to prevent it from being connected with the CGA-870 port in order to charge oxygen. Accordingly, a valve which has a separate single charge port in a cylinder has been used in order to charge oxygen.
By the way, a general valve in which a regulator has not been built is not been fitted with the CGA-870 port in the case of the single charge port valve, and thus includes a special regulator. The valve in which the special regulator has been built is expensive. As well, since width of selection of an apparatus which a user (or a patient) can install in an oxygen cylinder is greatly reduced, use of a valve having a single charge port decreases rapidly.
A valve which includes a CGA-870 port together with a charge port through which oxygen can be charged is disclosed in U.S. Pat. No. 6,386,235, in order to solve these problems.
By the way, if a check valve which is installed in the inside of a valve body in the case of the conventional valves, the entire valve should be separated from the cylinder and then the check valve should be maintained, repaired and replaced. As a result, a troublesome work may be caused. Also, if foreign matters are included in oxygen discharged through the CGA-870 port, a conventional valve filters out the foreign matters through a filter in a regulator connected with the CGA-870 port, but there is a limit to raise cleanliness of oxygen.
Moreover, the conventional valve can be used only for a post valve for an oxygen generation system for household use, but cannot be used for a post valve for a general medical care. Accordingly, when an oxygen cylinder is used for medical care, there is a problem that an additional post valve for general medical care should be provided for a prospective customer.